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Finding the Fourth Proportional to 139.05, 191.90 and 83.79

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Solution

The fourth proportional to 139.05, 191.90 and 83.79 is: 115.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.05 : 191.90 = 83.79 : x
  2. Step 2: Convert to fraction form
    139.05/191.90 = 83.79/x
  3. Step 3: Cross multiply
    139.05x = 191.90 × 83.79
  4. Step 4: Simplify right side
    139.05x = 16,079.30
  5. Step 5: Solve for x
    x = 16,079.30/139.05
  6. Step 6: Final answer
    x = 115.64

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.